The Gemological Institute of America said that the 1.76-carat diamond pictured at left was submitted with a fraudulent GIA inscription that matches an actual GIA report from 2015 for a natural diamond. The report number has been partially redacted for privacy reasons. (Photos courtesy of GIA/Photo credit: Troy Ardon)

Carlsbad, Calif.--In the latest issue of Gems & Gemology, the Gemological Institute of America reported finding a man-made diamond inscribed with a report number matching a mined diamond.

The article, authored by Christopher M. Breeding and Troy Ardon, states that the stone in question came through the lab’s Carlsbad facility.

A client, whom the GIA did not identify in the article, submitted the diamond for an updated grading report because they “noticed inconsistencies” with the GIA report information, the article states.

The diamond was inscribed with the number of a GIA report issued in 2015. That report was for a natural, untreated diamond graded as 1.74 carats, round brilliant cut, D color, Excellent cut grade and VVS1 clarity.

But when graders looked at the stone, the article states they found it was a round brilliant with Excellent cut grade but 1.76 carats, with F color and VS1 clarity.

Moreover, the GIA’s screening processes--which are done on every stone to determine if it is natural, treated, lab grown or a simulant--indicated that the diamond needed additional testing to determine its origin.

Examination with the DiamondView machine showed that the submitted stone was not a natural diamond but was grown using the high-pressure, high-temperature (HPHT) process.

The article also states that the FTIR (Fourier Transform Infrared) Spectra showed that the natural diamond from the original report--the one that matches the report number inscribed on the girdle of the man-made stone--was Type IA (about 95 percent of natural diamonds are this type) with aggregated nitrogen impurities, while the newly submitted diamond was Type IIb with boron impurities.

In addition, the GIA said upon closer examination, the font used for the number inscribed on the diamond’s girdle was different from the one used by GIA.

When asked if the GIA was investigating the source and scope of this fraudulent inscription, the lab said: “While we are aware of reports of fraudulent inscriptions, we rarely encounter this type of blatant fraud.”

The lab added that the stone was returned to the submitting client, which, it reiterated, was the one that noticed inconsistences with the GIA report information and sent in the diamond for an updated report.

In the article, the GIA advises members of the trade with any doubt about some aspect of a diamond to send it to a gem lab for verification.